Systems and methods for making thermoplastic products and compositions

Abstract

Thermoplastic compositions useful for roadway markings may be produced using a continuous systems and process methods that can reduce costs and improve product quality. Systems may comprise a feed system comprising a plurality of feeders and a mixing system comprising a mixer and a smoothing system. Each feeder may be configured to discharge a material at a feed rate according to a selected product formulation The mixing system may be configured to receive, heat, and combine the materials to produce a thermoplastic material, and discharge the thermoplastic material at a determined discharge rate.

That which is claimed: 
     
       1. A system for continuously producing thermoplastic material for roadway markings, the system comprising:
 a feed system comprising a plurality of feeders, each feeder configured to discharge a material at a feed rate according to a selected product formulation; 
 a mixing system configured to receive, heat, and combine the materials to produce a thermoplastic material, and discharge the thermoplastic material at a determined discharge rate; and 
 a control system configured to monitor process performance, product quality parameters, or combinations thereof, and adjust the feed rate of one or more of the feeders based on the discharge rate from the mixing system, the selected product formulation, or combinations thereof, 
 wherein the mixing system comprises a mixer and a smoothing system comprising a vibratory conveyer or screw conveyer, and 
 wherein the smoothing system is configured to receive the materials from the feed system and feed the materials to the mixer. 
 
     
     
       2. The system of  claim 1 , wherein each feeder comprises a vibratory conveyer, a screw conveyer, or a liquid charge line. 
     
     
       3. The system of  claim 1 , wherein the feed rate of at least one material is controlled by a weight differential of the feeder over time. 
     
     
       4. The system of  claim 1 , wherein the feed rate of at least one material is controlled by a volumetric flowrate from the feeder. 
     
     
       5. The system of  claim 1 , further comprising a transport system configured to receive the materials from the feed system and transport the materials to the mixing system. 
     
     
       6. The system of  claim 5 , wherein the transport system comprises a plurality of buckets, a belt conveyer, or a pneumatic conveyer. 
     
     
       7. The system of  claim 1 , wherein the mixer comprises a single screw mixer or a twin screw mixer. 
     
     
       8. The system of  claim 1 , wherein the mixer comprises more than one heating zone. 
     
     
       9. The system of  claim 1 , wherein the mixing system heats the materials to a temperature of 150° F. to 450° F. 
     
     
       10. The system of  claim 1 , further comprising a finishing system configured to receive the discharged thermoplastic material from the mixing system. 
     
     
       11. A method for continuously producing thermoplastic composition for roadway markings comprising:
 charging a feed system comprising a plurality of feeders with components of the thermoplastic composition; 
 discharging the components from the feeders at a determined feed rate; 
 feeding the components to a mixing system, wherein the mixing system comprises a mixer and a smoothing system; 
 mixing and heating the components in the mixing system; 
 blending at least a portion of the components in the smoothing system prior and feeding the blended components to the mixer; 
 discharging the thermoplastic composition; and 
 performing inline quality analysis and adjusting a feed rate of at least one component according to an inline quality analysis result. 
 
     
     
       12. The method of  claim 11 , further comprising adjusting the feed rate of the components based on the discharge rate of the thermoplastic composition. 
     
     
       13. The method of  claim 11 , further comprising transporting the components from the feed system to the mixing system by a transport system comprising one or more of a pneumatic conveyer, belt conveyer, or bucket conveyer. 
     
     
       14. The method of  claim 11 , further comprising heating the mixing system to a temperature of between 200° F. and 800° F. 
     
     
       15. The method of  claim 11 , wherein the components of the thermoplastic composition comprise:
 at least 3 weight percent polypropylene/polyethylene copolymer; 
 at least 18 weight percent binder; 
 at least 20 percent intermix of inorganic filler; and 
 at least one of:
 at least 1 weight percent of a polyethylene homopolymer wax, 
 at least 1 weight percent alkyd resin and soybean oil mixtures, 
 at least 0.5 weight percent of a UV stabilizing compound, 
 at least 1 weight percent of an alkyd resin modified glyceryl phthalate, or 
 at least 1 weight percent of a polyurethane.